People in small boats end up in the water for a variety of reasons. Rowers in inherently unstable crew shells often work out in unfavorable conditions of cold weather and rough water made worse by wind and should get out of the water as quickly as possible when the boat swamps or turns over. Any boat presents difficulties when a swimmer tries to lift him or herself over the gunnels (gunwales) and back into the boat or into a rescue boat.
A number of so-called folding ladders have been designed to aid in this difficulty but a majority of them are non-rigid rope ladders that are tossed over the side and all have the inherent problem of becoming unstable and difficult to climb because they tend to be forced under the bottom of the boat as the swimmer puts weight on the bottom rung. Such a folding ladder can be seen at:    (http://www.mysticmarinediscounts.com/sea-dog-corp-folding-ladder-5825011-ladder-five-step-rope.html)
A similar ladder is shown in FIG. 8 with rungs 100, rails 200, and rope 300 threaded through the rungs and rails. When held by the rope ends 400 designed to attach the ladder to a boat, gravity will drop the rails and rungs to straighten the rope, forming a ladder with parallel rails 500 and parallel rungs perpendicular to the rails. Rope ladders have no “stand-off” feature and most of the straight rigid ladders that hook over the side rail of the hull do not have any such feature. Without this “stand-off,” the swimmers fingers and toes on the rungs of most such ladders are therefore jammed up against the hull, making it difficult or less secure to get a safe grip while attempting to climb into the boat.
Similarly, there are many folding ladders on the market that have mechanical hinges that have to be opened as the ladder is deployed. See U.S. Pat. No. 6,145,621 to Nye. Not only are these mechanical parts potentially subject to jamming (making them difficult and time-consuming to open), but alternatively they may become loosened and unstable once they are opened and such movement could eventually compromise the safety and reliability of the ladder.
Likewise, almost all of the boat ladders on the market have to have some external means of attaching them to the boat—such as a bracket screwed permanently into the hull at a particular location into which the ladder is fitted during use, or to which the ladder itself is permanently attached in its folded position when not deployed for rescuing an overboard swimmer. This prohibits the ladder from being deployed at the position on the boat where it is needed. If the water is cold, the swimmer should get into the boat quickly to avoid hypothermia. Indeed, even the simple rope ladders have to be tied onto a rail or some other structure on the boat, which only adds additional time and uncertainty during an emergency rescue.
As for those rigid ladders which do have some sort of stand-off feature, the stand-off feature usually consists of some short legs extending horizontally from the side rails to hold the ladder away from the side of the hull. See U.S. Pat. No. 5,113,782 (McCarty), U.S. Pat. No. 2,924,291 (Tunstead), Des. 185,212 and U.S. Pat. No. 2,992,697 (Klages), and U.S. Pat. No. 3,512,608 (Huntley). These short legs sometimes fold out from the rails. This mechanical feature adds to the complexity of the device, potentially increases the time for deployment, and may in fact prove to be totally useless if it is at the bottom of the ladder and below the bottom of the hull on a shallow-draft boat like a jonboat (usually termed a “launch”) used by a crew coach to follow the shell during practice sessions, etc. These launches or chase boats are required to carry a safety equipment bag including life vests. If a quickly deployable ladder were available to fit in the safety equipment bag carried by chase boats, the rowers' safety would be enhanced in a simple and effective way.